We defined rectal cancer patients as those with an invasive tumor with its

distal edge <15 cm from the anal verge. We excluded 28 patients treated by transanal excision and three that represented a recurrence from another primary diagnosed before the beginning of our study period. We then conducted a retrospective review of the medical records of the remaining 159 patients to develop a database containing standard clinico-pathologic variables. The clinico-pathologic data recorded included the following patient characteristics: Inhibitors,research,lifescience,medical age at diagnosis, gender, AJCC stage, histological grade, LNCs, period of diagnosis [1995-2000 and 2001-2005], administration of neoadjuvant therapy, and performance of a detailed mesorectal excision. LNCs were determined from

the pathology report. For the purpose of analyses, LNCs were dichotomized in 4 different ways: Inhibitors,research,lifescience,medical ≥/<7, ≥/<10, ≥/<12, and ≥/<14, based on the median number of lymph nodes examined in the current study (i.e., 7) and values that appear in the literature (10, 12, and 14) (3,5,6). Univariate analysis (Kruskal-Wallis test) was used to explore the relationship between lymph node counts and the following variables: age (<70 yrs/>70 yrs), AJCC Stage, time of diagnosis (early — 1995-2000/late Inhibitors,research,lifescience,medical — 2001-2005), gender, administration of neoadjuvant therapy and the performance of mesorectal excision. Five-year OS was estimated by the Kaplan-Meier method and log rank testing was used to assess potential differences between Inhibitors,research,lifescience,medical groups. Cox proportional hazards modeling was used to examine the relationship between lymph node counts and survival, adjusting for patient age and stage at diagnosis. P-values ≤0.05 were considered statistically significant. Results Age, stage at diagnosis, year of diagnosis, and performance of MRE were patient Inhibitors,research,lifescience,medical characteristics that were significantly associated with LNCs. Patients less than

70 years old had more lymph nodes retrieved compared to those ≥70 years old (P<0.05). In univariate analysis, there was no statistically significant difference in LNCs by gender or by the use of neoadjuvant therapy (P>0.05). Patients treated during the later years of of the study were more likely to have more nodes retrieved (P>0.05). Patients with MRE performed had higher LNC, but not uniformly statistically significant for each cut point of LNCs used (Tables 1,​,22). Table 1 Patient characteristics by number of lymph nodes retrieved Table 2 Univariate analysis of patient characteristics by number of lymph nodes retrieved In our survival analysis, we observed that higher LNCs were associated with lower survival rates. ABT-869 supplier Although these differences in survival were not statistically significant, they were consistent for each cut point of LNCs used (Figure 1). In multivariate survival analysis using the Cox proportional hazards model, the apparent negative effect of increasing LNCs on survival did not persist.